What forms the roof of the infratemporal fossa?

The roof is formed by the infratemporal surface of the greater wing of the sphenoid and the squamous part of the temporal bone. It contains the foramen ovale and foramen spinosum.

Which nerves pass through the foramen ovale in the infratemporal fossa?

The mandibular nerve (V3), accessory meningeal artery, and the lesser petrosal nerve pass through the foramen ovale.

What are the main contents of the infratemporal fossa?

The main contents include muscles of mastication (medial and lateral pterygoid, lower part of temporalis), mandibular nerve and its branches, maxillary artery and branches, pterygoid venous plexus, chorda tympani, and otic ganglion.

Which artery is most clinically important in the infratemporal fossa?

The middle meningeal artery is clinically important as its injury can cause extradural hematoma.

What is the pterygoid venous plexus and why is it important?

The pterygoid venous plexus is a network of veins in the infratemporal fossa that drains blood from nasal cavity and nasopharynx and communicates with the cavernous sinus, providing a route for spread of infection.

Which muscle is primarily responsible for protrusion of the mandible?

The lateral pterygoid muscle is the primary muscle responsible for protrusion of the mandible.

How does the infratemporal fossa communicate with the pterygopalatine fossa?

The infratemporal fossa communicates with the pterygopalatine fossa through the pterygomaxillary fissure.

What is the function of the otic ganglion?

The otic ganglion provides parasympathetic secretomotor fibers to the parotid gland via the auriculotemporal nerve.

Why is the infratemporal fossa important in dental anesthesia?

The infratemporal fossa is the site where inferior alveolar nerve block is administered for dental procedures, making its anatomy critical for effective and safe anesthesia.

Infratemporal Fossa Anatomy Boundaries Contents Nerves Vessels and Clinical Importance

Q: What is the infratemporal fossa?

The infratemporal fossa is an irregular deep anatomical space located below the base of the skull, medial to the ramus of the mandible, and posterior to the maxilla. It contains muscles of mastication, major nerves, vessels, and parasympathetic ganglia.

Infratemporal Fossa

Definition

The infratemporal fossa is an irregular, wedge-shaped deep space located below the base of the skull, medial to the ramus of the mandible, and posterior to the maxilla. It is a major neurovascular and muscular compartment involved in mastication, facial sensation, and cranial–facial circulation.

Boundaries

Roof (Superior)

Infratemporal surface of greater wing of sphenoid
Squamous part of temporal bone
Contains:

* Foramen ovale – mandibular nerve (V3), accessory meningeal artery, lesser petrosal nerve

* Foramen spinosum – middle meningeal artery and vein, meningeal branch of V3

Lateral Wall

Ramus of mandible

Medial Wall

Lateral pterygoid plate (sphenoid)
Tensor veli palatini muscle

Anterior Wall

Posterior surface of maxilla

Posterior Wall

Tympanic plate
Mastoid and styloid processes of temporal bone
Separates infratemporal fossa from parotid region

Inferior Boundary

Open (continuous with tissues of the neck)

Muscles of Mastication

Medial pterygoid

* Origin: medial surface of lateral pterygoid plate

* Insertion: medial surface of mandibular angle

* Action: elevation and protrusion of mandible

Lateral pterygoid

* Two heads:

* Superior: greater wing of sphenoid

* Inferior: lateral pterygoid plate

* Insertion: neck of mandible and TMJ disc

* Action: depression, protrusion, lateral movement of mandible

Lower part of temporalis (tendon passing through fossa)

Nerves

Mandibular Nerve (V3) – Main Nerve

Exits skull via foramen ovale

Branches

Auriculotemporal nerve – sensation to temporal region and TMJ
Inferior alveolar nerve

* Gives nerve to mylohyoid

* Enters mandibular foramen

Lingual nerve – general sensation to anterior 2/3 of tongue
Buccal nerve – sensory to cheek
Motor branches to muscles of mastication

Chorda Tympani (Facial nerve branch)

Joins lingual nerve
Carries:

* Taste fibers (anterior 2/3 of tongue)

* Parasympathetic fibers to submandibular and sublingual glands

Otic Ganglion

Parasympathetic ganglion
Related to mandibular nerve
Secretomotor supply to parotid gland via auriculotemporal nerve

Arteries

Maxillary Artery (Terminal branch of external carotid)

Major arterial content of infratemporal fossa

Branches (Mandibular Part)

Deep auricular artery
Anterior tympanic artery
Middle meningeal artery
Accessory meningeal artery
Inferior alveolar artery

Veins

Pterygoid Venous Plexus

Extensive venous network
Drains into maxillary vein
Communicates with:

* Cavernous sinus (via emissary veins)

Clinical relevance: spread of infection

Ligaments

Sphenomandibular ligament

* Extends from spine of sphenoid to lingula of mandible

* Separates inferior alveolar nerve from lingual nerve

Communications

| Communication | Opening | Connects With |

| --------------------- | ------------------------ | ------------------------------ |

| Middle cranial fossa | Foramen ovale | V3, lesser petrosal nerve |

| Middle cranial fossa | Foramen spinosum | Middle meningeal artery |

| Pterygopalatine fossa | Pterygomaxillary fissure | Maxillary nerve and vessels |

| Orbit | Inferior orbital fissure | Infraorbital nerve and vessels |

| Temporal fossa | Deep to zygomatic arch | Temporalis muscle |

Clinical Importance

Inferior alveolar nerve block administered in infratemporal fossa
Middle meningeal artery injury → extradural hematoma
TMJ disorders involve lateral pterygoid
Spread of infection via pterygoid venous plexus to cavernous sinus
Trigeminal neuralgia may involve V3 branches